Development and calibration of heat transfer coefficient sensor for rotational state

A novel heat transfer coefficient sensor is introduced and the design, manufacture, and calibration are described. The intended application of this instrument was on a high rotational speed test disc. In the experiments, the heat transfer coefficient sensor was calibrated under static state and rotational state respectively. The calibration under the static state was accomplished in a pipe: the inside diameter (ID) was 0.048 m and the total length was 4 m, the distance between the sensor and the inlet of the pipe was 3.5 m; the standard value was measured using a self-made calibrator. The calibration under the rotational state was accomplished using a rotating disc: the diameter and thickness of the stainless disc were 800 mm and 25 mm, respectively; the sensor was installed at the location of r=250 mm; the rotating disc driven by a 30 kW direct current motor can supply the maximum rotational speed of 3000 r/min. The standard value under rotational state was provided by an approximate empirical formula. The results show that the designed sensor can measure heat transfer coefficient directly under rotational state and static state with good accuracy and stability; the correlation factor of K are constant under static state and rotational state.